The velocity of an electron in a certain Bohr orbit of H -atom bears the ratio $1: 275$ to the veloc

Question

The velocity of an electron in a certain Bohr orbit of H -atom bears the ratio $1: 275$ to the velocity of light. The quantum number ( $n$ ) of the orbit is\

Professor PC Thomas Classes · Answer

(b) : Velocity of electrons $=\frac{1}{275} 	imes$ velocity of light\ $=\frac{1}{275} 	imes 3 	imes 10^{10}=1.09 	imes 10^{8} \mathrm{~cm} \mathrm{~s}^{-1}$\ Since, $v_{n}=\frac{2 \pi e^{2}}{n h}$\ $1.09 	imes 10^{8}=\frac{2 	imes 3.14 	imes\left(4.803 	imes 10^{-10}ight)^{2}}{6.626 	imes 10^{-27} 	imes n} \quad 	herefore n=2$\